Heat in Texas, June 18, 2026

Area Forecast Discussion
National Weather Service Fort Worth TX
544 AM CDT Thu Jun 18 2026

...New AVIATION...

.KEY MESSAGES...

- A Heat Advisory is in effect area-wide this afternoon, with heat
  index values reaching 105 to 110 degrees.

- The arrival of a weak front will bring periodic chances for
  thunderstorms to the area from this evening through Saturday.
  Strong wind gusts and heavy rainfall will be the main hazards.

&&

.SHORT TERM...
(Tonight through Friday)
Issued at 1143 PM CDT Wed Jun 17 2026

The main concerns through the short term period are oppressive
heat this afternoon followed by the onset of convective chances
from this evening into Friday.

Southeasterly low-level flow with a fetch of rich Gulf moisture
will precede the arrival of a slow-moving cold front currently
making its way southward through the Southern Plains. The
persistent resupplying of near-surface moisture will maintain
mid/upper 70s dewpoints across most of the area through the
daytime, even during peak heating hours. As temperatures climb
into the mid/upper 90s, the heat and humidity will combine to
yield maximum heat index values of 105-110 area-wide, and a Heat
Advisory will go into effect at noon for all of North and Central
Texas. Max WBGTs will be near 90, and precautions should be taken
by anyone spending time outdoors to avoid heat-related illness.
It is possible that we'll need to extend a portion of the existing
Heat Advisory into Friday, although that decision and the spatial
area remain highly questionable at this time due to uncertainty
in the convective forecast, which will in turn have significant
implications on Friday's temperatures.

This evening, the main forecast concern will shift from heat to
convective chances, with recent high-res guidance taking on a
rather clear bimodal distribution of possible solutions for the
evening/overnight time period. The overall setup will consist of
an aggressively deepening surface low across West Texas in the
vicinity of the aforementioned upstream cold front, which will
also be juxtaposed with the low-level thermal ridge axis. Deep
mixing will send a dryline eastward through the Big Country by
late afternoon, which will encroach on our western counties by
this evening.

A handful of high-res CAMs are developing convection along the
dryline or near the dryline/front triple point across parts of
Northwest Texas by late afternoon, while others indicate rather
tranquil solutions this evening until more widespread convection
occurs overnight along the front. The members in each of these
groups share a commonality which is likely the key contributor to
the disparity in solutions, and that is their PBL schemes. Models
making use of local mixing schemes like the NAM Nest and NSSL WRF
maintain a much more shallow and under-mixed boundary layer this
afternoon, and keep dewpoints in the mid/upper 70s well into the
Big Country. This is artificially inflating the models' SBCAPE by
as much as a couple thousand J/kg, and their response is
essentially to auto-convect the atmosphere in order to resolve
such an extreme imbalance. This is then manifested in their
convective solutions by igniting a large complex and racing it
southeastward through much of the forecast area this evening and
tonight. Models making use of non-local PBL schemes, or at least a
hybrid scheme, indicate what currently seem to be a more
realistic scenario, as they aggressively mix out moisture and
depict surface dewpoints as much as 10-15 degrees lower than their
local scheme counterparts. The result is very deeply inverted-V
sounding profiles with surface dewpoint depressions of 40+
degrees, while their simulated convective attempts seemingly
struggle to overcome dry air entrainment. Models in this camp
include the FV3/HRRR/TTU WRF, which make use of either non-local
or hybrid mixing schemes. These solutions appear much more
realistic and also correspond more closely to global guidance
solutions as well, which hold off the bulk of the convective
chances until later in the evening and overnight period along the
frontal zone itself.

The forecast will attempt to capture these factors and scenarios to
the best possible ability. We'll indicate roughly 20-30% PoPs
across western portions of the area this evening to account for
the low but still non-zero potential that the explosive dryline
convective development actually does come to fruition. We'll
indicate higher PoPs overnight into Friday morning with the idea
that most convection will begin along the front later in the
evening with aid from the arrival of a shortwave in WNW flow
aloft. This convection will then likely develop a fairly robust
cold pool and surge southward through parts of North Texas during
the overnight and early morning period. Then, additional
convection during the daytime Friday will likely be tied to
wherever the actual frontal zone resides at that point, as well as
residual boundaries from any overnight and early morning
convection. While shear is marginal at best, typical of late June,
the potential for localized strong/severe wind gusts will
certainly exist owing to the thermodynamic environment. Heavy rain
and flooding could also be of concern if a complex begins to slow
or stall while training in a west to east fashion. PoPs will be
held to about 30-40% through the rest of Friday afternoon with
high uncertainty in placement and coverage due to the mesoscale
factors which will be driving any additional storm development.

&&

.LONG TERM...
(Friday night through next Wednesday)
Issued at 1143 PM CDT Wed Jun 17 2026

Additional convective chances will continue into the upcoming
weekend as shortwave disturbances traverse WNW flow through the
mid-levels while the old nearly stationary frontal zone provides
weakly focused ascent through Saturday. The presence of increased
cloud cover and some daytime precipitation will probably help to
keep most of the area below Heat Advisory criteria on Saturday,
but this may change on Sunday as convective activity looks to wind
down on the back side of a slow-moving upper trough axis. Medium-
range guidance is eager to keep a fairly active pattern in place
through at least the first half of next week with chances for
additional thunderstorm complexes arriving from the north on
nearly a daily basis. Areas unaffected by convection are likely to
make a return to Heat Advisory criteria though as humidity levels
look to remain elevated with daily highs in the mid 90s.

&&

.AVIATION...
(12Z TAFS)
Issued at 537 AM CDT Thu Jun 18 2026

MVFR stratus is rather unlikely to fill in sufficiently to result
in cigs this morning, and category reductions have been removed
the Metroplex TAFs based on recent trends. A couple hours of cigs
remain possible at Waco where these conditions will continue to be
Tempo'd. VFR will prevail through today with a southeast wind
around 10 kts. Convective activity is expected to develop across
parts of Northwest Texas and Oklahoma later this evening which
will move towards and eventually through North Texas overnight
into Friday morning. TS will be shown roughly from 09-15z in the
extended DFW TAF with low confidence in timing. This window may
need to be adjusted backward or forward by a few hours in
subsequent TAFs, but confidence in TS occurrence is high enough to
warrant VCTS/Tempo inclusions even at this time range.
Thunderstorms are likely to be accompanied by gusty outflow winds
which would cause a temporary northwest wind shift upon their
arrival.

&&

.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected at this time.

&&

.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth    97  79  90  75 /   0  70  60  70
Waco                96  79  90  75 /   0  20  30  60
Paris               93  75  85  73 /   0  60  60  70
Denton              96  76  89  74 /   0  70  60  60
McKinney            96  77  88  74 /   0  70  60  70
Dallas              98  79  92  76 /   0  70  60  70
Terrell             96  78  90  74 /   0  40  50  70
Corsicana           97  79  93  77 /   0  20  40  60
Temple              97  79  92  76 /   0  20  30  60
Mineral Wells       98  75  88  72 /   0  70  60  60

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from noon today to 9 PM CDT this evening for
TXZ091>095-100>107-115>123-129>135-141>148-156>162-174-175.

&&

SHORT TERM...Stalley
LONG TERM....Stalley
AVIATION...Stalley